/*
 * Copyright (C) 2012 Square, Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.cliff.hsj.api.common;

import com.google.gson.TypeAdapter;
import com.squareup.okhttp.MediaType;
import com.squareup.okhttp.RequestBody;
import com.squareup.okhttp.ResponseBody;
import java.io.IOException;
import java.io.OutputStreamWriter;
import java.io.Reader;
import java.io.Writer;
import java.nio.charset.Charset;
import okio.Buffer;
import retrofit.Converter;

final class GsonConverter<T> implements Converter<T> {
  private static final MediaType MEDIA_TYPE = MediaType.parse("application/json; charset=UTF-8");
  private static final Charset UTF_8 = Charset.forName("UTF-8");

  private final TypeAdapter<T> typeAdapter;

  GsonConverter(TypeAdapter<T> typeAdapter) {
    this.typeAdapter = typeAdapter;
  }

  @Override public T fromBody(ResponseBody body) throws IOException {
    Reader in = body.charStream();
    try {
      return typeAdapter.fromJson(in);
    } finally {
      try {
        in.close();
      } catch (IOException ignored) {
      }
    }
  }

  @Override public RequestBody toBody(T value) {
    Buffer buffer = new Buffer();
    Writer writer = new OutputStreamWriter(buffer.outputStream(), UTF_8);
    try {
      typeAdapter.toJson(writer, value);
      writer.flush();
    } catch (IOException e) {
      throw new AssertionError(e); // Writing to Buffer does no I/O.
    }
    return RequestBody.create(MEDIA_TYPE, buffer.readByteString());
  }
}
